The present invention relates generally to a cylinder block for an internal combustion engine and, particularly to a structure of a site for a starter motor.
Upon starting, a crankshaft of an automotive engine is turned by a starter motor up to a required engine speed. The starter motor can not be installed freely to the cylinder block, that is, its mounting position must be selected under certain restrictions. Additionally, owing to an improvement in the engine performance and requirements of an increased occupant room space, an engine room space and the starter motor mounting space are both limited. Under such conditions, the starter motor is mounted to the engine at a starter motor mounting flange which is formed at a rear portion of the cylinder block (refer to Japanese Utility Model Publication No. 61-53568).
In the past, the starter motor has been mounted to the cylinder block with side bolts at a starter motor mounting flange which was formed in correspondence to the rearmost one of main bearing caps. With such structure, however, since the flange was obstructive to tightening operation of a side bolt for the rearmost main bearing cap, this side bolt was omitted, or the flange was formed on the cylinder block to rear of a mounting portion of this side bolt. Thus, problems are encountered such that there is insufficient rigidity for mounting of the starter motor and a transmission, and for supporting of a crankshaft due to the absence of the side bolt for the rearmost main bearing cap.
An object of the present invention is to provide a structure of a mounting site for a starter motor, which mounting site is of the adequate rigidity and allows a bolt for a main bearing cap easy to mount and remove.